- - UDF not working
(http://www.cfd-online.com/Forums/fluent-udf/105379-udf-not-working.html)

daniel_ortega79

July 29, 2012 08:18

UDF not working

I am using a UDF for inlet velocity boundary(vx=2*y).when I interpret my UDF it doesn't show any error.But after selecting my UDF in B.C. when I want to initialize, it shows a constant velocity value. Is there anyone who knows what the problem is?

flotus1

July 30, 2012 03:03

Unless you show us the UDF you used, you will have to wait for a psychic with basic knowledge in UDF programming.
I can tell you that these people are quite rare ;)

akm

July 30, 2012 12:02

'Initialize' provides an initial solution over the entire domain. Through the Fluent GUI you can give only a single initial value for the entire domain. If you want the initial solution to be of the form Vx=2y, you will have to write an initialization macro (DEFINE_INIT).

However, im guessing you have written a udf for inlet B.C. (DEFINE_PROFILE), which will be used as the inlet velocity condition for obtaining the solution.

The initial solution is given to the solver as a starting point for the calculation, and should not affect the final solution (unless, of course, it is way off which will lead to a divergence).

akm

July 30, 2012 12:05

Quote:

Originally Posted by flotus1
(Post 374284)

Unless you show us the UDF you used, you will have to wait for a psychic with basic knowledge in UDF programming.
I can tell you that these people are quite rare ;)

@Alex.. yes, people like me are rare :D hahaa

daniel_ortega79

July 30, 2012 16:37

thank you guys! yes I used (define_profile) for my inlet velocity. In fact the problem was due to the written code. I guess after this project I'll be more psychic than before :rolleyes: